1. Field of the Invention
The present invention relates to a recording tape cartridge.
2. Description of the Related Art
A recording tape cartridge (magnetic tape cartridge) at which a magnetic tape, which is used as a data recording/replaying medium for a computer or the like, is wound onto a single reel and this reel is accommodated in a case made of synthetic resin has been known hitherto. At a distal end (free end) of a magnetic tape thereof, a leader member, such as a leader pin, a leader tape, a leader block or the like is fixed. Drawing-out means, which is provided at a drive device, draws the leader member out through an opening aperture of the recording tape cartridge and winds the magnetic tape, which is fixed to the leader member, onto a winding reel of the drive device.
A circular opening is formed through a lower face of the recording tape cartridge, and a reel gear is provided in an annular form at a center of the lower face of the reel and exposed through this opening. A drive gear, which is provided at a rotation shaft of the drive device, meshes with the reel gear. With this structure, the reel is driven to rotate. When the reel of the recording tape cartridge and the winding reel of the drive device are rotated at the same time, data can be recorded to the magnetic tape and/or data that has been recorded to the magnetic tape can be replayed.
At a recording tape cartridge with such a structure, the leader member is a coupling member which is coupled with the drive device side winding reel in a state in which the magnetic tape is pulled tight. However, types of the opening aperture formed in the case, a door which opens and closes the opening aperture and so forth differ for the different types of leader member. For example, in a case with a leader block, the opening aperture is formed at a corner portion at a side in a direction of loading of the recording tape cartridge (the case) into a drive device, and the leader block is engaged so as to close off the opening aperture. That is, the leader block is structured so as to also serve as a door for closing the opening aperture.
This leader block is structured by a stiff body. Therefore, in comparison to a tape-form leader tape, an operation of engagement with the drive device side drawing-out means can be performed more easily, which is advantageous in that abrasion and damage to an engaging portion of the drawing-out means is less likely to occur. Furthermore, when the opening aperture is at the corner portion of the case, this is advantageous in that an angle of drawing-out of the leader block can be freely selected in design of the drive device. For example, design is possible so as to draw out the leader block along a shortest distance to the winding reel, and design is possible so as to complete the operation of drawing-out of the magnetic tape in a short time.
However, if a leader block is engaged at a corner portion of a recording tape cartridge (a case) at times of non-use (when the recording tape cartridge is not loaded at a drive device), there is a problem in that if the corner portion is subjected to an impact, due to dropping or the like, it is likely that the case will be warpingly deformed and that the leader block will fall out from the corner portion.
When the leader block is detached and thrown out from the case due to dropping or the like, a user will consequently be subjected to concern as to whether the functionality of the recording tape cartridge has been affected, and will be subjected to concern as to whether or not the recording tape cartridge will operate in the drive device if repaired by hand. Moreover, in practice, creases may be formed in the magnetic tape when the recording tape cartridge is dropped and the leader block detaches from the case. Furthermore, when the leader block improperly detaches, because the leader block itself functions as a door, there is a problem in that dustproofing of the recording tape cartridge is breached.
Accordingly, it has conventionally been thought that impacts due to dropping and the like can be mitigated and effects on the leader block kept to a minimum by, for example, forming the corner portion in a form which is itself easily deformed by warping. However, such structures by themselves have been insufficient as countermeasures for preventing detachment of leader blocks.
Accordingly, as shown in FIGS. 18A and 18B, for example, provision of a flat plate-form engaging member 120 at a vicinity of an opening 114 of a recording tape cartridge 110 has been considered. A pair of support members 116 are provided standing apart by a predetermined spacing at an inner face of a case 112 at the vicinity of the opening 114. A shaft portion 122, which is formed at one end of the engaging member 120, is rotatably supported at the pair of support members 116. A protrusion 124, which is formed at the other end of the engaging member 120, engages with an engaging groove 128. The engaging groove 128 is formed at a fixing portion 130B side of a leader block 130, at which side the magnetic tape is attached. (See, for example, the specification of U.S. Pat. No. 5,232,180.)
At a time of non-use of the recording tape cartridge 110, as shown in FIG. 18A, the protrusion 124 engages with the engaging groove 128 of the leader block 130, and detachment of the leader block 130 from the case 112 is prevented. Then, at a time of use of the recording tape cartridge 110, as shown in FIG. 18B, a release member 126 enters through an aperture 118, which is formed through the case 112, and the aforementioned other end of the engaging member 120, including the protrusion 124, is pushed up by the release member 126. The engaging member 120 rotates upward about the shaft portion 122, as a result of which the protrusion 124 is removed from the engaging groove 128. Consequently, the leader block 130 can be taken out from the case 112.
However, because this engaging member 120 is a structure in which the shaft portion 122 is supported at the pair of support members 116 which are provided standing apart by the predetermined spacing at the inner face of the case 112 and the engaging member 120 rotates upward about the shaft portion 122 to be removed from the engaging groove 128, there is a problem in that it is necessary to provide a large amount of space for disposition thereof in the vicinity of the opening 114. That is, as shown in FIG. 19A, because the pair of support members 116 are provided standing apart by the predetermined spacing, space is required in a lateral direction of the case 112 (a direction intersecting a height direction of the case 112), and as shown in FIG. 19B, because the release stroke is higher than a height of the leader block 130, space is required in the height direction of the case 112. Thus, the large amount of space for disposition is required in the vicinity of the opening 114, and the recording tape cartridge 110 is larger, which is a problem.